NARRATIVE OF THE CRUISE. 
753 
with Cryptolaria and Perisiphonia in the essential structure of the hydrocaulus, 
which consists, as in those genera, of an axial and a peripheral system, but with 
differences which will not allow Gramma, ria to be generically united with Cryptolaria 
or Perisiphonia. 
“ Among other groups, the Lafoeidse, Haleciidse, and Campanularidse have as yet been 
the most completely examined. These are represented by some new genera, and by 
many new and beautiful species. Their investigation has in some instances necessitated 
the revision of existing definitions, while it has considerably extended our knowledge of 
Hy droid morphology. 
“ The number of gymnoblastic Hydroids brought home by the Challenger is but 
small. Among these, however, has been found an exceedingly interesting form 
which must be regarded as the type of a new genus, and which is especially 
remarkable from the peculiarity of its habitat, living as it does parasitically beneath 
the dorsal plates of an Annelid. It was found in this situation by Professor MTntosh 
while engaged in his examination of the Challenger Annelids, and by him sent to me 
for determination. 
“ Among the results of the Challenger dredgings must, however, be specially recorded 
the discovery of a gigantic Tubularian (fig. 2 6 5), which was dredged in the North Pacific from 
depths of 1875 and 2900 fathoms. It is referable to the genus Monocaulus, a near ally 
of Corymorpha. One of the specimens whose dimensions were noted by Professor Wyville 
Thomson and Mr. Moseley immediately after its capture was found to measure 9 inches 
from tip to tip of the extended tentacles, which form the proximal tentacular circlet ; while 
-its stem rose from its point of attachment to a height of 7 feet 4 inches. This great 
Tubularian affords indeed an example of a Hydroid attaining dimensions far exceeding 
the maximum which would have been hitherto, thought possible in Hydroid life — a char- 
acter to which the vast depth whence it was obtained gives additional significance.” 
On the passage across the Pacific on the- 35'th parallel, the ship was, for the 
first week after leaving Japan, favoured with fresh southerly and southwesterly 
winds, and occasionally, as far as the meridian of 165°,E., with drizzling rain, the 
weather being cloudy and foggy. From the meridian of 165° E. to that of 180°, 
which was reached on July 3rd, light winds from west round south to east were 
experienced, with moderately fine weather, but the atmosphere continued very damp. 
After crossing the 180th meridian, light easterly winds necessitated the vessel being 
steered north to the 38th parallel, in which moderate westerly breezes were experienced 
to the meridian of 160° W., the weather still continuing damp and cloudy. After pass- 
ing the 160th meridian in lat. 38° N., wiuds from the southeastward were experienced, 
varying from south to east until within a short distance of the Sandwich Islands. 
The section across the western portion of the North Pacific, from Japan to Honolulu, 
